Both the manga and the anime focus on the steadily deteriorating conditions of the Keroro Platoon, a group of two-foot-tall frog-like invaders from the planet Keron, who continuously try to conquer the world, but fail miserably each time. The platoon's leader, Sergeant Keroro, is easily distracted , and would rather spend his time making plastic Gundam models and surfing the Internet than destroying Earth, much to the chagrin of the bellicose corporal, Giroro. Aside from Keroro's laziness, the largest obstacle in the way of their mission is the Hinata Family, a trio of humans in whose care Keroro finds himself after the Keron army deserts him on earth. Keroro is kept busy with manual labour and constant abuse, primarily from the family daughter Natsumi. Aside from Keroro, there are four other members in the Keroro platoon. Each one of these find themselves in the care of a human, who are all tied to the Hinatas in some way throughout the events in the Anime and Manga.
This story has the part which was created by referencing Wikipedia, so the licence of GFDL is applied to this story.